The invention pertains to a luminaire with at least one LED (light emitting diode) as a light source. Such a LED has a limited light ray angle for emitted light radiation.
The corresponding angle for a LED is for example 15° to 220°, wherein the angle is generally fixed by a small lens structure of the LED. With respect to such light sources, it has to be considered that the efficiency of an LED is in fact relatively high, whereby, for example, a maximum of just 20% of the applied energy is in fact converted to visible light. It is a further characteristic of LEDs that the produced usable spectrum by such conversion is very narrow and there will be no portion of the radiation in the infrared area. The rest of the applied energy will be converted into heat. To avoid any damage of the LED by such produced heat, this heat will be discharged by a cooling body, active cooling, liquid cooling or the like. Otherwise, the lifespan of the LED and also its light production will be negatively influenced or reduced by the high heat impact. In general it can be said, that at temperatures of 120° C. or higher the corresponding semiconductor crystal of the LED will be damaged and will result in lasting drawbacks with respect to lifespan, light color, light production and further drawbacks to the LED. Such radiation angle refers to an angle of the light cone emitted by the light source, which can be used for efficient lighting and is also called effective luminous flux.